For materials to be used as bone void fillers, which have to interact with human tissue, it is advantageous to make the biomaterials as biocompatible and bioactive as possible. This can be achieved principally by at least two routes—developing stable biocompatible materials or resorbable materials allowing new bone tissue to substitute the biomaterial. The first route to make more stable materials, e.g. PMMA-based materials or Ca-aluminate-based materials, is especially suitable for osteoporotic clinical situations. For active or young patients a resorbable material, e.g. soluble glasses and phosphate-based materials, may be the most attractive route, where interaction with living tissue is more pronounced. It is well known that calcium aluminates and calcium silicates can have a considerably higher compressive strength than those of the present resorbable materials (in the order of 100 MPa).
The traditional resorbable phases contain oxides of Ca and P (or S). Ca-phosphates and or Ca-sulphates and glass containing CaO, P2O5, SiO2 and Na2O are typical representatives for this low-mechanical strength category of bioelements.
In EP 1 123 081 B1 and EP 0 555 807 Ca-silicate is mentioned as an additional phase for drug uses (less than 10%) and for bone substitute products as an additional divalent compound. Regarding biocompability of Ca-silicate materials, work have been done on the endodontic treatment material Proroot or MTA and on Wollastonite materials. See J. Saidon, et al, “Cells and tissue reactions to mineral trioxide aggregate and Portland cement”, Oral surgery medicine pathology, April (2003) 483-489. Wollastonite is an established biomaterial in the form of sintered ceramic pieces. A survey of bone cements is found in S. M. Kenny and M. Buggy, “Bone cements and fillers: A Review”, Journal of Materials Science: Materials in Medicine, 14 (2003) 923-938.
In view of the prior art materials for use, particularly in, bone void filling, there is a need for a biocompatible material exhibiting resorbability and sufficiently high strength, and thus load-bearing capacity, shortly after application, as well as later on.